Erlotinib having the chemical name N-(3-ethynylphenyl)-6,7-bis(2-methoxyethoxy)-4-quinazolinamine, is reported in PCT Publication No. WO. 96/30347 and its equivalent U.S. Pat. No. 5,747,498 (1998). Although, the preparation of its hydrochloride salt is mentioned in this patent, its Polymorphic forms and their properties are not discussed. None of its solid state properties excepting melting point are disclosed in this patent.
Subsequently, PCT Publication No. WO. 01/34574 and its equivalent U.S. Pat. No. 6,900,221 (2005) described polymorphic Forms-A and B of Erlotinib HCl, and mentioned that the polymorphic form ‘B’ is thermodynamically more stable. This patent, also identified that the product of U.S. Pat. No. 5,747,498 was a mixture of polymorphic Forms A and B. A method of preparing pure polymorphic Form-B of Erlotinib. HCl (I) free of the polymorphic Form-A is also claimed in U.S. Pat. No. 6,900,221. The powder XRD data of both the crystal Forms A and B are disclosed in this patent.
The patent WO 2004/072049 corresponding to the International Application No PCT/EP 2004/001244 discloses a novel polymorph E along with its DSC and XRD characteristics and claims improved stability over the polymorph A. However, this polymorphic form E is prepared in (α,α,α)-trifluorotoluene which is highly flammable and dangerous for the environment. It is also an expensive solvent and not convenient to handle on an industrial scale.